So my car was hopping a little at high boost after the EPL tune. I thought maybe clutch or wheel spin, but then I got a CEL for misfire.

Had the codes read and misfire on cyl 4. I had just changed plugs to the IK20's about 2000 miles ago, so I didn't think plugs. I had the original coils, so I put the new 997 coils in.

No change. I did pull a plug while I was doing coils and I thought they looked weird, but I thought, nah, they are practically new...

So had the codes read again and now misfire was in 1 & 2. So I thought maybe plugs. Got some Bosch FR6 LDC copper plugs in and no more issues...

Here is a picture of the Denso plug. Top is mine and bottom is a new one. You can't see it extremely well, but the little tip has basically been burned down... Guess the IK20's are no good for high boost. I am running 1.1bar on K16's.



Thanks to Tony at Stuttgart here in town for helping me SOOOOO much!!!

 

What gap were you running on the plugs?

What heat range were those plugs relative to factory?

I don't see why the Iridium plugs would cause a misfire where the copper plugs do not if you have the correct plug and gap for your application.

 

I used the factory gap from Denso (.044") and I think they are the same heat range as stock plugs for the TT. The IK22 are a colder plug I think...

 

agreed the iks are bad news!! im running denso pk20prp8 gapped at .027 i run a ton of bost with a mix of 110 and 104 and they are rock solid

 

IMO, typically with a lot of boost you need to run a lot smaller gap. You could be blowing out your spark with a large gap combined with a lot of boost. A colder heat range plug is also a good idea with significant boost.

This is a pretty good read on spark plug performance from NGK:

http://www.ngksparkplugs.ca/tech-info-spark-plugs.cfm

 

Good read there! I am pretty new to blown engines so I am learning... Would the gap being too wide cause the plug to basically melt on the tip like mine? Maybe they got too hot cause of the compression and gap?

 

just giving youa heads up you dont have a blower on your car. you have turbos, forced induction, or boosted would be a better way to say it cause blower are usually for v8's and belt driven

no harm intended purely educational intent

 

Seriously? I thought I was driving a Grand Prix GTP all this time... Come on man, give me a break.

Blowers blow, turbos blow, you... well....

 

Subscribing

 

Well, you would think that if they list the IK20 for the 996TT, they would gap it right or at least tell you what to gap it at... I have never had to gap a plug differently... It is just a learning thing, but I spent a lot of time "learning" that I should have gapped the plugs... And this car is not a good one to learn on! Although, I can do my plugs in 2.5 hours now!

 

I'm surprised. I used Iridium plugs in my Supra as they were the ONLY thing that wouldn't melt down quickly - I could go a YEAR on them running meth, race gas, the works without misfire. I did gap them but you have to be REAL careful doing that with these since the pin is so brittle. Iridium is a VERY hard material, if it melted down I'd be surprised if another plug held up much better if it's got the same heat range and gap...

 

I have put 8000 miles on iridium plugs making between 700 and 800hp on the Turbo with no ill effects thus far.... Mine would have been the equivalent of IK24 though. I gapped them down to .030 as well

Justin

 

Anyone know the correct gap for the Bosch FR6? And where did you get the gap info?

 

Hi, Larry.

Back in the US - arrived last night!

Here's the page from the 996TT manual. Plug gap 1.6 +/- 0.2 mm

Best wishes for the holidays!

Jon

 

First, why would you not call or PM Tony and ask him what to run, it's his tune? As far as I know, he only recommends one plug. I have never had misfire issues since I changed.
Second, ALWAYS double check your plugs out of the box. You never know if someone drop a box a pinched one down a little.